1. Field of the Invention
The present invention relates generally to variable resistors and, more specifically, to an improved guided variable resistor that minimizes noise and wear resulting from use.
2. Description of the Related Art
Variable resistors have typically utilized a sliding element resembling a brush wherein the brush slides across a surface of a resistive element and a conductive element to vary resistance. However, noise is generated as a result of the brush element lifting from the resistor element as it slides across the resistor element and the conductive element. Obviously, noise generation becomes more of a problem as the need for steady resistance increases.
There is an additional problem in that the sliding brush element makes it difficult to achieve a smooth sliding motion. The rough sliding motion, caused by the large amount of friction that typically exists between the sliding element and the resistive and conductive elements, adversely affects the degree to which the variance of resistance can be controlled.
Another problem has been performance deterioration over time. This results from the constant frictional wear caused by the sliding of the brush element across the resistor and conductive elements each time the resistance is changed.
At least one prior art variable resistor has used a rolling contact member that is biased against the resistive and conductive elements by a spring. Such devices, however, are complicated, requiring a large number of components and a lengthy assembly time.
A need therefore still exists in the art to provide an improved sliding type variable resistor which minimizes wear and noise and which is simple in construction.